The details are shown here <a href="http://wiki.opengatecollaboration.org/index.php/Users_Guide:Data_output">http://wiki.opengatecollaboration.org/index.php/Users_Guide:Data_output</a> Those 46 columns in the coincidence.dat are basically two sets of singles. So it depends on your setup but I'm only using the ones for "volume IDs", which will be 12-17 and 35-40. Hope this helps. Taku Yamanaka <div class="gmail_quote">2013/1/7 jehangir khan <<a href="mailto:jehangir.kahn@gmail.com" target="_blank">jehangir.kahn@gmail.com</a>> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Gate users! I have question related to image reconstruction of cylindrical PET simulation. I got ascii output [Concidence.dat, single.dat etc]. can someone sacrifice short time to explain little about how should I proceed using coincidence data,because this file has 46 coulmns.which coulmns should I consider or skip, or any useful suggestion to proceed I shall appreciate for your time Regards _______________________________________________ Gate-users mailing list <a href="mailto:Gate-users@lists.opengatecollaboration.org">Gate-users@lists.opengatecollaboration.org</a> <a href="http://lists.opengatecollaboration.org/mailman/listinfo/gate-users" target="_blank">http://lists.opengatecollaboration.org/mailman/listinfo/gate-users</a> </blockquote></div> -- Hokkaido University, Graduate school of medicine, medical physics and engineering D1 Taku Yamanaka <a href="mailto:takuyama@med.hokudai.ac.jp" target="_blank">takuyama@med.hokudai.ac.jp</a> --